Add web component json files

[ChristianMurphy]

Adding a web component json file to a project and to a package gives editors the ability to auto complete tag and attribute names of custom elements.

references:
WICG/webcomponents#776

[ChristianMurphy]

Cross linking: https://github.com/elmsln/wcfactory/issues/325

[btopro]

@ChristianMurphy would there be interest in a stand alone command that wcfactory could then ingest as well as uPortal (or anyone) to accomplish this? I think the fastest way to achieve this file would be:

• require an argument as to where to look for the files (possibly pegged to the lerna https://github.com/uPortal-contrib/uPortal-web-components/blob/master/lerna.json#L3 packages variable)
• run polymer analyze (which works on any component not just polymer) to get the meta data / property documentation required
• parse / combine these files to generate the definitions on the fly

Or some other way; whatever gets it automated and built the fastest and if it can happen agnostic o our two projects via some tooling integration then all the better. This could be something that the patternfly and open-wc groups could also utilize as they have similar goals

[ChristianMurphy]

I'd be interested in a stand alone command.

Not sure if that would work for Vue or React components though, both use MutationObserver instead of observedAttributes.
https://github.com/vuejs/vue-web-component-wrapper/blob/master/src/index.js#L105-L128
https://github.com/PixelsCommander/ReactiveElements/blob/36a65a69bae59442c6092dba74efa07c90511012/src/reactive-elements.js#L26-L31

Worth a try though.